The proposed project will investigate the appetite for sugar, polysaccharide, and starch in laboratory rats. In particular, the project will follow-up our recent discovery that rats have a taste and avid appetite for starch-derived polysacchardes, and will overeat and become obese when given access to polysaccharide solutions. The specific aims of the project are (I) to compare the gustatory and behavioral responses of rats to sugars, polysacharides and starch: (II) determine the ontological development of polysaccharide appetite; (III) determine the functional significance of the rats' different carbohydrate tastes; (IV) determine the role of taste and postingestive factors in the long-term preferences for carbohydrates; and (V) determine the influence of diet form and macronutrient composition on carbohydrate appetite and obesity. This research, which involves the fields of sensory physiology, psychobiology, and nutrition, will provide new information on the interaction of taste and nutrition in the control of food intake and body weight.